Theoretical research analysis shows that many authors have noted a positive effect of mild anxiety, called the optimal level of anxiety or adaptive anxiety on children development. A study conducted in 2010-2014 was designed to investigate the levels of anxiety in children of primary school age. The study involved 241 elementary school student aged 7 - 11 years. Anxiety was diagnosed by Children's Manifest Anxiety Scale, or CMAS, adapted by A.M. Prikhozhan. The article presents a statistical and qualitative analysis of anxiety manifestations throughout the primary school age. The study revealed the ratio of anxiety levels in primary school children from first to fourth grade, the results are compared with those of previous studies of anxiety. The research allowed to identify the main elementary school periods when children have higher anxiety and often need psychological help.